NFL players at high risk for Alzheimer's disease and other neurodegenerative disorders

Summer is coming to an end and fall activities will soon, including the bone-jarring sport of football. Practice will soon begin for all skill levels ranging from Pop Warner for kids as young as five years to NFL pros. It is common knowledge that playing football carries a high risk of physical injury.

Now, a new study reports that National Football League (NFL) players have a significantly higher risk of dying from a neurodegenerative disorder such as Alzheimer’s disease and amyotrophic lateral sclerosis (ALS). The study, which was conducted by researchers affiliated with the Centers for Disease Control and Prevention (CDC) published their findings online on September 5 in the journal Neurology.

The researchers designed a study to analyze neurodegenerative causes of death, specifically Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis, among professional football players. The study group comprised 3,439 NFL players with at least five pension-credited playing seasons from 1959 to 1988. Vital status (whether they were living) was established through 2007. For analysis purposes, the players were placed into two groups based on characteristics of position played: nonspeed players (linemen) and speed players (all other positions except punter/kicker). External comparisons with the US population used standardized mortality ratios (SMRs); internal comparisons between speed and nonspeed player positions used standardized rate ratios (SRRs).

The researchers found that overall player mortality compared with that of the US population was reduced (SMR: 0.53; range: 0.48–0.59). Neurodegenerative mortality was increased using both underlying cause of death rate files (SMR: 2.83; range: 1.36–5.21) and multiple cause of death (MCOD) rate files (SMR: 3.26; range: 1.90–5.22). Of the neurodegenerative causes, results were elevated (using MCOD rates) for both amyotrophic lateral sclerosis (SMR: 4.31; range: 1.73–8.87) and Alzheimer’s disease (SMR: 3.86; range: 1.55–7.95). In internal analysis, higher neurodegenerative mortality was observed among players in speed positions compared with players in nonspeed positions.

The authors concluded that the neurodegenerative mortality in this study population was three times higher than that of the general US population. Furthermore, for two of the major neurodegenerative subcategories, Alzheimer’s disease and amyotrophic sclerosis, the rate was four times higher than the general population. They noted that their results were consistent with recent studies that suggest an increased risk of neurodegenerative disease among football players.

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Other studies have reported the risk of brain damage from contact sports. Last April, UCLA Health System announced that its Brain Injury Research Center will receive funding from the National Collegiate Athletic Association (NCAA) to conduct research on sports concussions. Sports-related concussions have been estimated to be between 1.6 million to 3.8 million players each year in the United States. Many of these athletes are high school, college, or professional football players. Many players chalk it up to an acceptable risk of an activity that can provide one with millions of dollars of revenue. Others express concern, while other players who have suffered brain damage as a result of the sport have filed lawsuits against the National Football League (NFL). On the state level, California lawmakers have enacted a new statute for 2012: school sports teams must bench an athlete suspected of sustaining a concussion or head injury until cleared by a healthcare provider.

UCLA reports that the study, which began this summer, will encompass collaborations between specialists in neuropsychology, neurosurgery, pediatric neurology, and sports medicine. The Brain Injury Research Center will be directly involved in all phases of the study: design and execution; data collection and management; and the analysis and dissemination of the results. In an attempt to study the short-term and long-term effects of concussions, the researchers plan to evaluate more than 1,000 male and female college athletes competing in 11 different sports, both contact and non-contact.

Sophisticated techniques will be employed for data collection. Accelerometer devices inside football helmets will gather data on the head-impact dynamics associated with concussions in athletes. Dr. Giza noted that a new mouth guard also is being developed by the company X2 Impact; the device can sense and record head impacts and will allow researchers to include additional sports in which helmets are not worn. He explained, "The mouth guards will open the door to studies in a much broader range of sports, such as soccer, basketball, and field hockey, as well as better comparisons between male and female athletes.”

In order to gain a more comprehensive understanding of traumatic brain injuries, the study will continue after the athletes complete college. They will be examined for any long-term effects of head injuries. Those long-term effects recently led to heated discussions after autopsies on deceased players in contact sports revealed the development of a degenerative condition known as chronic traumatic encephalopathy.

In view of the fact that head injuries also occur in high school athletes, the consortium is hopeful to expand the study beyond the college level. Thus, the researchers are seeking additional funding so that it can begin enrolling athletes as early as high school; these athletes will be followed through college and even into professional careers.

Take home message:
If you are a parent with an aspiring athlete, it would be prudent to steer him or her in the direction of a non-contact sport. Injuries—and fatalities—have been reported from football players, including high school levels. Although baseball is generally regarded as a safe sport, last month a Little League player was struck in the chest with a baseball; he incurred a cardiac arrest and suffered major damage.